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Java Simplified. Extensions and Useful Constructs for the Java Platform. Codeprimate Elements (a.k.a. cp-elements) is a Java library and micro-framework used to simplify the development of software applications written in Java. Elements packages several APIs into one library in order to address various application concerns and aspects of software design and development collectively and conveniently. Elements is a highly simple, yet robust and proven library built on solid OO principles, software design patterns and best practices to effectively solve common and reoccurring problems in software development.

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/*
 * Copyright 2016 Author or Authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.cp.elements.lang;

/**
 * The Identifiable interface defines a contract for uniquely identifying objects of a given type.
 *
 * @author John J. Blum
 * @see java.lang.Comparable
 * @since 1.0.0
 */
@SuppressWarnings("unused")
public interface Identifiable> {

  /**
   * Returns the identifier uniquely identifying this object.
   *
   * @return the value uniquely identifying this object.
   */
  T getId();

  /**
   * Sets the identifier uniquely identifying this object.
   *
   * @param id value of type T assigned as this object's unique identifier.
   */
  void setId(T id);

  /**
   * Determines whether this {@link Identifiable} object is new indicated with a {@literal null} identifier.
   *
   * @return a boolean value indicating whether this {@link Identifiable} object is new.
   */
  default boolean isNew() {
    return getId() == null;
  }

  /**
   * Determines whether this {@link Identifiable} object is non-new indicated with a non-{@literal null} identifier.
   *
   * @return a boolean value indicating whether this {@link Identifiable} object is non-new.
   * @see #isNew()
   */
  default boolean isNotNew() {
    return !isNew();
  }

  /**
   * Builder method used to set this {@link Identifiable} object's id.
   *
   * @param  Subclass type of this {@link Identifiable} object.
   * @param id value of type T assigned as this object's unique identifier.
   * @return a reference to this {@link Identifiable}.
   * @see #setId(Comparable)
   */
  @SuppressWarnings("unchecked")
  default > S identifiedBy(T id) {
    setId(id);
    return (S) this;
  }
}